To simplify the understanding, data is typically represented graphically in all kinds of electronic as well as paper-based media. For example, charts are commonly used for presenting data on web pages, online- and print magazines. Charts depicted in print media can be digitized by capturing the chart with a camera or a scanning device for providing a digital representation of the chart. A large variety of different chart types exists, e.g. bar charts, pie charts, doughnut charts or the like. Charts of a particular type, e.g. a scatter plot, may vary greatly e.g. in respect to the colorings or textures, the size, type and position of scatter points, the position and design of text labels and other criteria.
In case the data that is graphically represented in a digital scatter plot image shall be used as a basis for further data processing, e.g. statistical analyses, or to be visualized in a user-specific way, the data values represented in the scatter plot currently need to be entered in a computer system manually. For example, the x and y positions and the axis or data point labels may be entered with a real keyboard or virtual keyboard (especially keyboards displayed on a tablet PC's or smartphone's touchscreen of limited size and functionality). Entering said data manually can be cumbersome and error prone, in particular for large scatter plots comprising dozens or even hundreds of data points.
The complexity and diversity of digital scatter plots has hitherto precluded a completely automated extraction of data from scatter plots. Thus, in many cases a user had to type in the data represented by a scatter plot in a target application by hand.
Existing programs for digitizing plot images do not fully-automatically extract data points and/or fully-automatically identify plot axes. Further, these programs do not automatically identify the maximum and minimum values of axes ranges. Finally, these programs do not automatically identify chart titles, series names, or axes labels. It is therefore not possible to quickly and accurately extract data from plot images using existing programs.